Citation

Summary

This dataset provides an estimate of 2015 cheatgrass percent cover in the northern Great Basin at 250 meter spatial resolution. The dataset was generated by integrating eMODIS NDVI satellite data with independent variables that influence cheatgrass germination and growth into a regression-tree model. Individual pixel values range from 0 to 100 with an overall mean value of 9.85 and a standard deviation of 12.78. A mask covers areas not classified as shrub/scrub or grass/herbaceous by the 2001 National Land Cover Database. The mask also covers areas higher than 2000 meters in elevation because cheatgrass is unlikely to exist at more than 2% cover above this threshold. Cheatgrass is an invasive grass that has invaded much of the Great [...]

Summary

This dataset provides an estimate of 2015 cheatgrass percent cover in the northern Great Basin at 250 meter spatial resolution. The dataset was generated by integrating eMODIS NDVI satellite data with independent variables that influence cheatgrass germination and growth into a regression-tree model. Individual pixel values range from 0 to 100 with an overall mean value of 9.85 and a standard deviation of 12.78. A mask covers areas not classified as shrub/scrub or grass/herbaceous by the 2001 National Land Cover Database. The mask also covers areas higher than 2000 meters in elevation because cheatgrass is unlikely to exist at more than 2% cover above this threshold. Cheatgrass is an invasive grass that has invaded much of the Great Basin. It grows from seed, usually early in spring, and rapidly matures, produces seed, and dies. Its presence can deplete early-season moisture reserves and put native vegetation at a competitive disadvantage. In addition, it contributes fine fuels that facilitate fire ignition and fire spread. Rangeland fires are often stand replacing events in sagebrush communities, commuities which historically dominated much of the northern Great Basin. Increasing fire return intervals, increasing fire intensities, land management practices, and development have all contributed to the fragmentation of sagebrush ecosystems, which are critical for greater sagegrouse survival.

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Purpose

This dataset is designed to provide a near-real-time estimate of cheatgrass in the northern Great Basin for 2015 to optimize land management efforts to control cheatgrass, preserve critical greater sagegrouse habitat, and inform fire control and prevention. Timely maps of dynamic cheatgrass percent cover are needed in early summer for these purposes. Research shows that cheatgrass percent cover is spatially and temporally highly variable in arid and semiarid environments because cheatgrass germination and growth is highly sensitive to annual weather, especially precipitation totals and timing. Precipitation totals and timing are also spatially and temporally highly variable in these environments; therefore, this dataset is only representative of cheatgrass percent cover during 2015 and does not represent any other time period.